There's an Onion article we rather liked a while back that neatly lampooned the shaver business, in which Gilette, frustrated by Wilkinson Sword's move to three-blade razors, promptly shouts: "F**k 'em - we're going to five blades."

A similar war - real this time - appears to be breaking out between HD DVD and Blu-ray Disc (BD) proponents. Desperate to get HD DVD's capacity up to something closer to its rival's, Toshiba last week unveiled (http://www.theregister.co.uk/2005/05/11/toshiba_45gb_hd-dvd/) a three-layer disc that can hold 45GB.

Now - with more than a little 'f**k you!' implied if not stated - TDK has announced a four-layer BD.

The beast holds up to 100GB of data. More to the point, it's recordable, and according to TDK, can support a write-speed double that of today's 50GB BD-Rs - or 6x (216Mbps), in other words.

The disc uses TDK's Durabis coating, announced (http://www.theregister.co.uk/2005/01/07/tdk_durabis/) last January, which finally allows BDs to be used without a protective cartridge, though they remain rather less resilient to scratches than DVDs.

Getting discs up to 100GB and beyond - 200GB appears to be the limit - was always part of the Blu-ray plan. TDK has talked about making 100GB BDs in the past. Alas, today's announcement, made in Japanese-language newspaper Nihon Keizai Shimbun, gives no indication as to when these discs might actually appear on the market. ®

Related stories

Toshiba unveils 45GB HD DVD (http://www.theregister.co.uk/2005/05/11/toshiba_45gb_hd-dvd/)
Toshiba slams Blu-ray/ HD DVD convergence claims (http://www.theregister.co.uk/2005/05/10/toshiba_slams_hd_claims/)
Sony to add Blu-ray and DSD to Vaio (http://www.theregister.co.uk/2005/04/14/sony_blu-ray_dsd_viao/)
Sony 'open' to Blu-ray Disc/HD DVD bonding talks (http://www.theregister.co.uk/2005/04/13/sony_blu-ray_hd-dvd_talks/)
Apple backs Blu-ray (http://www.theregister.co.uk/2005/03/10/apple_backs_blu-ray/)
Alliance touts holographic disc 'revolution' (http://www.theregister.co.uk/2005/02/07/hvd_alliance_founded/)
Game firms back Blu-ray (http://www.theregister.co.uk/2005/01/07/game_cos_back_blu-ray/)
Blu-ray Disc maker to 'abolish cartridges' (http://www.theregister.co.uk/2005/01/07/tdk_durabis/)